In fabrication of integrated circuit chips, it is conventional to form many identical chips concurrently on a common wafer of semiconductor material, and subsequently dice the wafer into individual chips for packaging. It is well-known to use a wafer probe in order to test the individual chips prior to dicing and packaging.
A wafer probe is described in U.S. patent application Ser. No. 318,084 filed Nov. 4, 1981. That wafer probe comprises a plate-like substrate member of dielectric material. In use, the substrate member is mounted at one end in a probe station, and it carries several probe elements, such as gold beads, at its opposite end. The probe elements are connected to a measurement instrument by transmission lines formed on the substrate member. In order to carry out a test, the probe elements are brought into contact with pads of an integrated circuit under test, and the signals at those pads are transmitted to the measurement instrument.
A disadvantage of the wafer probe described in U.S. patent application Ser. No. 318,084 filed Nov. 4, 1981 is that the relatively low input impedance of the transmission lines (e.g. 50 ohms) results in the possibility that the testing operation might disturb significantly the signal level at the probed pads.
An active wafer probe using an amplifier implemented in silicon and spaced from the probe station is manufactured by G. G. B. Industries of Gillette, N.J.
E. Strid and K. Gleason, "A DC-12GHz Monolithic GaAsFET Distributed Amplifier", IEEE Transactions on Microwave Theory and Techniques, vol. MTT-30, No. 7, pp. 969-975, July 1982, discloses a wafer probe and suggests that passive or active circuit elements may be mounted on the probe tip.